﻿//using System;
//using System.Collections;
//using System.Text;
//using System.Text.RegularExpressions;

//namespace StableDiffusionTools.Framework
//{


//    /// <summary>
//    /// This Class implements the Difference Algorithm published in
//    /// "An O(ND) Difference Algorithm and its Variations" by Eugene Myers
//    /// Algorithmica Vol. 1 No. 2, 1986, p 251.  
//    /// 
//    /// There are many C, Java, Lisp implementations public available but they all seem to come
//    /// from the same source (diffutils) that is under the (unfree) GNU public License
//    /// and cannot be reused as a sourcecode for a commercial application.
//    /// There are very old C implementations that use other (worse) algorithms.
//    /// Microsoft also published sourcecode of a diff-tool (windiff) that uses some tree data.
//    /// Also, a direct transfer from a C source to C# is not easy because there is a lot of pointer
//    /// arithmetic in the typical C solutions and i need a managed solution.
//    /// These are the reasons why I implemented the original published algorithm from the scratch and
//    /// make it avaliable without the GNU license limitations.
//    /// I do not need a high performance diff tool because it is used only sometimes.
//    /// I will do some performace tweaking when needed.
//    /// 
//    /// The algorithm itself is comparing 2 arrays of numbers so when comparing 2 text documents
//    /// each line is converted into a (hash) number. See DiffText(). 
//    /// 
//    /// Some chages to the original algorithm:
//    /// The original algorithm was described using a recursive approach and comparing zero indexed arrays.
//    /// Extracting sub-arrays and rejoining them is very performance and memory intensive so the same
//    /// (readonly) data arrays are passed arround together with their lower and upper bounds.
//    /// This circumstance makes the LCS and SMS functions more complicate.
//    /// I added some code to the LCS function to get a fast response on sub-arrays that are identical,
//    /// completely deleted or inserted.
//    /// 
//    /// The result from a comparisation is stored in 2 arrays that flag for modified (deleted or inserted)
//    /// lines in the 2 data arrays. These bits are then analysed to produce a array of Item objects.
//    /// 
//    /// Further possible optimizations:
//    /// (first rule: don't do it; second: don't do it yet)
//    /// The arrays DataA and DataB are passed as parameters, but are never changed after the creation
//    /// so they can be members of the class to avoid the paramter overhead.
//    /// In SMS is a lot of boundary arithmetic in the for-D and for-k loops that can be done by increment
//    /// and decrement of local variables.
//    /// The DownVector and UpVector arrays are alywas created and destroyed each time the SMS gets called.
//    /// It is possible to reuse tehm when transfering them to members of the class.
//    /// See TODO: hints.
//    /// 
//    /// diff.cs: A port of the algorythm to C#
//    /// Created by Matthias Hertel, see http://www.mathertel.de
//    /// This work is licensed under a Creative Commons Attribution 2.0 Germany License.
//    /// see http://creativecommons.org/licenses/by/2.0/de/
//    /// 
//    /// Changes:
//    /// 2002.09.20 There was a "hang" in some situations.
//    /// Now I undestand a little bit more of the SMS algorithm. 
//    /// There have been overlapping boxes; that where analyzed partial differently.
//    /// One return-point is enough.
//    /// A assertion was added in CreateDiffs when in debug-mode, that counts the number of equal (no modified) lines in both arrays.
//    /// They must be identical.
//    /// 
//    /// 2003.02.07 Out of bounds error in the Up/Down vector arrays in some situations.
//    /// The two vetors are now accessed using different offsets that are adjusted using the start k-Line. 
//    /// A test case is added. 
//    /// 
//    /// 2006.03.05 Some documentation and a direct Diff entry point.
//    /// 
//    /// 2006.03.08 Refactored the API to static methods on the Diff class to make usage simpler.
//    /// 2006.03.10 using the standard Debug class for self-test now.
//    ///            compile with: csc /target:exe /out:diffTest.exe /d:DEBUG /d:TRACE /d:SELFTEST Diff.cs
//    /// </summary>

//    public class Diff
//    {

//        /// <summary>details of one difference.</summary>
//        public struct Item
//        {
//            /// <summary>Start Line number in Data A.</summary>
//            public int StartA;
//            /// <summary>Start Line number in Data B.</summary>
//            public int StartB;

//            /// <summary>Number of changes in Data A.</summary>
//            public int DeletedA;
//            /// <summary>Number of changes in Data A.</summary>
//            public int InsertedB;

//            public Item(int startA, int startB, int deleted, int insert) : this()
//            {
//                StartA = startA;
//                StartB = startB;
//                DeletedA = deleted;
//                InsertedB = insert;
//            }
//        } // Item

//        /// <summary>
//        /// Shortest Middle Snake Return Data
//        /// </summary>
//        private struct SMSRD
//        {
//            internal int x, y;
//            // internal int u, v;  // 2002.09.20: no need for 2 points 
//        }


//        #region self-Test

//#if (SELFTEST)
//    /// <summary>
//    /// start a self- / box-test for some diff cases and report to the debug output.
//    /// </summary>
//    /// <param name="args">not used</param>
//    /// <returns>always 0</returns>
//    public static int Main(string[] args) {
//      StringBuilder ret = new StringBuilder();
//      string a, b;

//      System.Diagnostics.ConsoleTraceListener ctl = new System.Diagnostics.ConsoleTraceListener(false);
//      System.Diagnostics.Debug.Listeners.Add(ctl);

//      System.Console.WriteLine("Diff Self Test...");
      
//      // test all changes
//      a = "a,b,c,d,e,f,g,h,i,j,k,l".Replace(',', '\n');
//      b = "0,1,2,3,4,5,6,7,8,9".Replace(',', '\n');
//      System.Diagnostics.Debug.Assert(TestHelper(Diff.DiffText(a, b, false, false, false))
//        == "12.10.0.0*", 
//        "all-changes test failed.");
//      System.Diagnostics.Debug.WriteLine("all-changes test passed.");
//      // test all same
//      a = "a,b,c,d,e,f,g,h,i,j,k,l".Replace(',', '\n');
//      b = a;
//      System.Diagnostics.Debug.Assert(TestHelper(Diff.DiffText(a, b, false, false, false))
//        == "",
//        "all-same test failed.");
//      System.Diagnostics.Debug.WriteLine("all-same test passed.");

//      // test snake
//      a = "a,b,c,d,e,f".Replace(',', '\n');
//      b = "b,c,d,e,f,x".Replace(',', '\n');
//      System.Diagnostics.Debug.Assert(TestHelper(Diff.DiffText(a, b, false, false, false))
//        == "1.0.0.0*0.1.6.5*",
//        "snake test failed.");
//      System.Diagnostics.Debug.WriteLine("snake test passed.");

//      // 2002.09.20 - repro
//      a = "c1,a,c2,b,c,d,e,g,h,i,j,c3,k,l".Replace(',', '\n');
//      b = "C1,a,C2,b,c,d,e,I1,e,g,h,i,j,C3,k,I2,l".Replace(',', '\n');
//      System.Diagnostics.Debug.Assert(TestHelper(Diff.DiffText(a, b, false, false, false))
//        == "1.1.0.0*1.1.2.2*0.2.7.7*1.1.11.13*0.1.13.15*",
//        "repro20020920 test failed.");
//      System.Diagnostics.Debug.WriteLine("repro20020920 test passed.");
      
//      // 2003.02.07 - repro
//      a = "F".Replace(',', '\n');
//      b = "0,F,1,2,3,4,5,6,7".Replace(',', '\n');
//      System.Diagnostics.Debug.Assert(TestHelper(Diff.DiffText(a, b, false, false, false))
//        == "0.1.0.0*0.7.1.2*", 
//        "repro20030207 test failed.");
//      System.Diagnostics.Debug.WriteLine("repro20030207 test passed.");
      
//      // Muegel - repro
//      a = "HELLO\nWORLD";
//      b = "\n\nhello\n\n\n\nworld\n";
//      System.Diagnostics.Debug.Assert(TestHelper(Diff.DiffText(a, b, false, false, false))
//        == "2.8.0.0*", 
//        "repro20030409 test failed.");
//      System.Diagnostics.Debug.WriteLine("repro20030409 test passed.");

//    // test some differences
//      a = "a,b,-,c,d,e,f,f".Replace(',', '\n');
//      b = "a,b,x,c,e,f".Replace(',', '\n');
//      System.Diagnostics.Debug.Assert(TestHelper(Diff.DiffText(a, b, false, false, false))
//        == "1.1.2.2*1.0.4.4*1.0.6.5*", 
//        "some-changes test failed.");
//      System.Diagnostics.Debug.WriteLine("some-changes test passed.");

//      System.Diagnostics.Debug.WriteLine("End.");
//      System.Diagnostics.Debug.Flush();

//      return (0);
//    }


//    public static string TestHelper(Item []f) {
//      StringBuilder ret = new StringBuilder();
//      for (int n = 0; n < f.Length; n++) {
//        ret.Append(f[n].deletedA.ToString() + "." + f[n].insertedB.ToString() + "." + f[n].StartA.ToString() + "." + f[n].StartB.ToString() + "*");
//      }
//      // Debug.Write(5, "TestHelper", ret.ToString());
//      return (ret.ToString());
//    }
//#endif
//        #endregion


//        /// <summary>
//        /// Find the difference in 2 texts, comparing by textlines.
//        /// </summary>
//        /// <param name="TextA">A-version of the text (usualy the old one)</param>
//        /// <param name="TextB">B-version of the text (usualy the new one)</param>
//        /// <returns>Returns a array of Items that describe the differences.</returns>
//        public Item[] DiffText(string TextA, string TextB)
//        {
//            return (DiffText(TextA, TextB, false, false, false));
//        } // DiffText


//        /// <summary>
//        /// Find the difference in 2 text documents, comparing by textlines.
//        /// The algorithm itself is comparing 2 arrays of numbers so when comparing 2 text documents
//        /// each line is converted into a (hash) number. This hash-value is computed by storing all
//        /// textlines into a common hashtable so i can find dublicates in there, and generating a 
//        /// new number each time a new textline is inserted.
//        /// </summary>
//        /// <param name="TextA">A-version of the text (usualy the old one)</param>
//        /// <param name="TextB">B-version of the text (usualy the new one)</param>
//        /// <param name="trimSpace">When set to true, all leading and trailing whitespace characters are stripped out before the comparation is done.</param>
//        /// <param name="ignoreSpace">When set to true, all whitespace characters are converted to a single space character before the comparation is done.</param>
//        /// <param name="ignoreCase">When set to true, all characters are converted to their lowercase equivivalence before the comparation is done.</param>
//        /// <returns>Returns a array of Items that describe the differences.</returns>
//        public static Item[] DiffText(string TextA, string TextB, bool trimSpace, bool ignoreSpace, bool ignoreCase)
//        {
//            // prepare the input-text and convert to comparable numbers.
//            Hashtable h = new Hashtable(TextA.Length + TextB.Length);

//            // The A-Version of the data (original data) to be compared.
//            DiffData DataA = new DiffData(DiffCodes(TextA, h, trimSpace, ignoreSpace, ignoreCase));

//            // The B-Version of the data (modified data) to be compared.
//            DiffData DataB = new DiffData(DiffCodes(TextB, h, trimSpace, ignoreSpace, ignoreCase));

//            h = null; // free up hashtable memory (maybe)

//            LCS(DataA, 0, DataA.Length, DataB, 0, DataB.Length);
//            return CreateDiffs(DataA, DataB);
//        } // DiffText


//        /// <summary>
//        /// Find the difference in 2 arrays of integers.
//        /// </summary>
//        /// <param name="ArrayA">A-version of the numbers (usualy the old one)</param>
//        /// <param name="ArrayB">B-version of the numbers (usualy the new one)</param>
//        /// <returns>Returns a array of Items that describe the differences.</returns>
//        public static Item[] DiffInt(int[] ArrayA, int[] ArrayB)
//        {
//            // The A-Version of the data (original data) to be compared.
//            DiffData DataA = new DiffData(ArrayA);

//            // The B-Version of the data (modified data) to be compared.
//            DiffData DataB = new DiffData(ArrayB);

//            LCS(DataA, 0, DataA.Length, DataB, 0, DataB.Length);
//            return CreateDiffs(DataA, DataB);
//        } // Diff


//        /// <summary>
//        /// This function converts all textlines of the text into unique numbers for every unique textline
//        /// so further work can work only with simple numbers.
//        /// </summary>
//        /// <param name="aText">the input text</param>
//        /// <param name="h">This extern initialized hashtable is used for storing all ever used textlines.</param>
//        /// <param name="trimSpace">ignore leading and trailing space characters</param>
//        /// <returns>a array of integers.</returns>
//        private static int[] DiffCodes(string aText, Hashtable h, bool trimSpace, bool ignoreSpace, bool ignoreCase)
//        {
//            // get all codes of the text
//            string[] Lines;
//            int[] Codes;
//            int lastUsedCode = h.Count;
//            object aCode;
//            string s;

//            // strip off all cr, only use lf as textline separator.
//            aText = aText.Replace("\r", "");
//            Lines = aText.Split('\n');

//            Codes = new int[Lines.Length];

//            for (int i = 0; i < Lines.Length; ++i)
//            {
//                s = Lines[i];
//                if (trimSpace)
//                    s = s.Trim();

//                if (ignoreSpace)
//                {
//                    s = Regex.Replace(s, "\\s+", " ");            // TODO: optimization: faster blank removal.
//                }

//                if (ignoreCase)
//                    s = s.ToLower();

//                aCode = h[s];
//                if (aCode == null)
//                {
//                    lastUsedCode++;
//                    h[s] = lastUsedCode;
//                    Codes[i] = lastUsedCode;
//                }
//                else
//                {
//                    Codes[i] = (int)aCode;
//                } // if
//            } // for
//            return (Codes);
//        } // DiffCodes


//        /// <summary>
//        /// This is the algorithm to find the Shortest Middle Snake (SMS).
//        /// </summary>
//        /// <param name="DataA">sequence A</param>
//        /// <param name="LowerA">lower bound of the actual range in DataA</param>
//        /// <param name="UpperA">upper bound of the actual range in DataA (exclusive)</param>
//        /// <param name="DataB">sequence B</param>
//        /// <param name="LowerB">lower bound of the actual range in DataB</param>
//        /// <param name="UpperB">upper bound of the actual range in DataB (exclusive)</param>
//        /// <returns>a MiddleSnakeData record containing x,y and u,v</returns>
//        private static SMSRD SMS(DiffData DataA, int LowerA, int UpperA, DiffData DataB, int LowerB, int UpperB)
//        {
//            SMSRD ret;
//            int MAX = DataA.Length + DataB.Length + 1;

//            int DownK = LowerA - LowerB; // the k-line to start the forward search
//            int UpK = UpperA - UpperB; // the k-line to start the reverse search

//            int Delta = (UpperA - LowerA) - (UpperB - LowerB);
//            bool oddDelta = (Delta & 1) != 0;

//            /// vector for the (0,0) to (x,y) search
//            int[] DownVector = new int[2 * MAX + 2];

//            /// vector for the (u,v) to (N,M) search
//            int[] UpVector = new int[2 * MAX + 2];

//            // The vectors in the publication accepts negative indexes. the vectors implemented here are 0-based
//            // and are access using a specific offset: UpOffset UpVector and DownOffset for DownVektor
//            int DownOffset = MAX - DownK;
//            int UpOffset = MAX - UpK;

//            int MaxD = ((UpperA - LowerA + UpperB - LowerB) / 2) + 1;

//            // Debug.Write(2, "SMS", String.Format("Search the box: A[{0}-{1}] to B[{2}-{3}]", LowerA, UpperA, LowerB, UpperB));

//            // init vectors
//            DownVector[DownOffset + DownK + 1] = LowerA;
//            UpVector[UpOffset + UpK - 1] = UpperA;

//            for (int D = 0; D <= MaxD; D++)
//            {

//                // Extend the forward path.
//                for (int k = DownK - D; k <= DownK + D; k += 2)
//                {
//                    // Debug.Write(0, "SMS", "extend forward path " + k.ToString());

//                    // find the only or better starting point
//                    int x, y;
//                    if (k == DownK - D)
//                    {
//                        x = DownVector[DownOffset + k + 1]; // down
//                    }
//                    else
//                    {
//                        x = DownVector[DownOffset + k - 1] + 1; // a step to the right
//                        if ((k < DownK + D) && (DownVector[DownOffset + k + 1] >= x))
//                            x = DownVector[DownOffset + k + 1]; // down
//                    }
//                    y = x - k;

//                    // find the end of the furthest reaching forward D-path in diagonal k.
//                    while ((x < UpperA) && (y < UpperB) && (DataA.data[x] == DataB.data[y]))
//                    {
//                        x++; y++;
//                    }
//                    DownVector[DownOffset + k] = x;

//                    // overlap ?
//                    if (oddDelta && (UpK - D < k) && (k < UpK + D))
//                    {
//                        if (UpVector[UpOffset + k] <= DownVector[DownOffset + k])
//                        {
//                            ret.x = DownVector[DownOffset + k];
//                            ret.y = DownVector[DownOffset + k] - k;
//                            // ret.u = UpVector[UpOffset + k];      // 2002.09.20: no need for 2 points 
//                            // ret.v = UpVector[UpOffset + k] - k;
//                            return (ret);
//                        } // if
//                    } // if

//                } // for k

//                // Extend the reverse path.
//                for (int k = UpK - D; k <= UpK + D; k += 2)
//                {
//                    // Debug.Write(0, "SMS", "extend reverse path " + k.ToString());

//                    // find the only or better starting point
//                    int x, y;
//                    if (k == UpK + D)
//                    {
//                        x = UpVector[UpOffset + k - 1]; // up
//                    }
//                    else
//                    {
//                        x = UpVector[UpOffset + k + 1] - 1; // left
//                        if ((k > UpK - D) && (UpVector[UpOffset + k - 1] < x))
//                            x = UpVector[UpOffset + k - 1]; // up
//                    } // if
//                    y = x - k;

//                    while ((x > LowerA) && (y > LowerB) && (DataA.data[x - 1] == DataB.data[y - 1]))
//                    {
//                        x--; y--; // diagonal
//                    }
//                    UpVector[UpOffset + k] = x;

//                    // overlap ?
//                    if (!oddDelta && (DownK - D <= k) && (k <= DownK + D))
//                    {
//                        if (UpVector[UpOffset + k] <= DownVector[DownOffset + k])
//                        {
//                            ret.x = DownVector[DownOffset + k];
//                            ret.y = DownVector[DownOffset + k] - k;
//                            // ret.u = UpVector[UpOffset + k];     // 2002.09.20: no need for 2 points 
//                            // ret.v = UpVector[UpOffset + k] - k;
//                            return (ret);
//                        } // if
//                    } // if

//                } // for k

//            } // for D

//            throw new ApplicationException("the algorithm should never come here.");
//        } // SMS


//        /// <summary>
//        /// This is the divide-and-conquer implementation of the longes common-subsequence (LCS) 
//        /// algorithm.
//        /// The published algorithm passes recursively parts of the A and B sequences.
//        /// To avoid copying these arrays the lower and upper bounds are passed while the sequences stay constant.
//        /// </summary>
//        /// <param name="DataA">sequence A</param>
//        /// <param name="LowerA">lower bound of the actual range in DataA</param>
//        /// <param name="UpperA">upper bound of the actual range in DataA (exclusive)</param>
//        /// <param name="DataB">sequence B</param>
//        /// <param name="LowerB">lower bound of the actual range in DataB</param>
//        /// <param name="UpperB">upper bound of the actual range in DataB (exclusive)</param>
//        private static void LCS(DiffData DataA, int LowerA, int UpperA, DiffData DataB, int LowerB, int UpperB)
//        {
//            // Debug.Write(2, "LCS", String.Format("Analyse the box: A[{0}-{1}] to B[{2}-{3}]", LowerA, UpperA, LowerB, UpperB));

//            // Fast walkthrough equal lines at the start
//            while (LowerA < UpperA && LowerB < UpperB && DataA.data[LowerA] == DataB.data[LowerB])
//            {
//                LowerA++; LowerB++;
//            }

//            // Fast walkthrough equal lines at the end
//            while (LowerA < UpperA && LowerB < UpperB && DataA.data[UpperA - 1] == DataB.data[UpperB - 1])
//            {
//                --UpperA; --UpperB;
//            }

//            if (LowerA == UpperA)
//            {
//                // mark as inserted lines.
//                while (LowerB < UpperB)
//                    DataB.modified[LowerB++] = true;

//            }
//            else if (LowerB == UpperB)
//            {
//                // mark as deleted lines.
//                while (LowerA < UpperA)
//                    DataA.modified[LowerA++] = true;

//            }
//            else
//            {
//                // Find the middle snakea and length of an optimal path for A and B
//                SMSRD smsrd = SMS(DataA, LowerA, UpperA, DataB, LowerB, UpperB);
//                // Debug.Write(2, "MiddleSnakeData", String.Format("{0},{1}", smsrd.x, smsrd.y));

//                // The path is from LowerX to (x,y) and (x,y) ot UpperX
//                LCS(DataA, LowerA, smsrd.x, DataB, LowerB, smsrd.y);
//                LCS(DataA, smsrd.x, UpperA, DataB, smsrd.y, UpperB);  // 2002.09.20: no need for 2 points 
//            }
//        } // LCS()


//        /// <summary>Scan the tables of which lines are inserted and deleted,
//        /// producing an edit script in forward order.  
//        /// </summary>
//        /// dynamic array
//        private static Item[] CreateDiffs(DiffData DataA, DiffData DataB)
//        {
//            ArrayList a = new ArrayList();
//            Item aItem;
//            Item[] result;

//            int StartA, StartB;
//            int LineA, LineB;

//            LineA = 0;
//            LineB = 0;
//            while (LineA < DataA.Length || LineB < DataB.Length)
//            {
//                if ((LineA < DataA.Length) && (!DataA.modified[LineA])
//                  && (LineB < DataB.Length) && (!DataB.modified[LineB]))
//                {
//                    // equal lines
//                    LineA++;
//                    LineB++;

//                }
//                else
//                {
//                    // maybe deleted and/or inserted lines
//                    StartA = LineA;
//                    StartB = LineB;

//                    while (LineA < DataA.Length && (LineB >= DataB.Length || DataA.modified[LineA]))
//                        // while (LineA < DataA.Length && DataA.modified[LineA])
//                        LineA++;

//                    while (LineB < DataB.Length && (LineA >= DataA.Length || DataB.modified[LineB]))
//                        // while (LineB < DataB.Length && DataB.modified[LineB])
//                        LineB++;

//                    if ((StartA < LineA) || (StartB < LineB))
//                    {
//                        // store a new difference-item
//                        aItem = new Item(StartA, StartB, LineA - StartA, LineB - StartB);
//                        a.Add(aItem);
//                    } // if
//                } // if
//            } // while

//            result = new Item[a.Count];
//            a.CopyTo(result);

//            return (result);
//        }

//        public static int[] DiffCharCodes(string aText, bool ignoreCase)
//        {
//            int[] Codes;

//            if (ignoreCase)
//                aText = aText.ToUpperInvariant();

//            Codes = new int[aText.Length];

//            for (int n = 0; n < aText.Length; n++)
//                Codes[n] = aText[n];

//            return Codes;
//        } // DiffCharCodes

//    } // class Diff

//    /// <summary>Data on one input file being compared.  
//    /// </summary>
//    internal class DiffData
//    {

//        /// <summary>Number of elements (lines).</summary>
//        internal int Length;

//        /// <summary>Buffer of numbers that will be compared.</summary>
//        internal int[] data;

//        /// <summary>
//        /// Array of booleans that flag for modified data.
//        /// This is the result of the diff.
//        /// This means deletedA in the first Data or inserted in the second Data.
//        /// </summary>
//        internal bool[] modified;

//        /// <summary>
//        /// Initialize the Diff-Data buffer.
//        /// </summary>
//        /// <param name="data">reference to the buffer</param>
//        internal DiffData(int[] initData)
//        {
//            data = initData;
//            Length = initData.Length;
//            modified = new bool[Length + 2];
//        } // DiffData

//    } // class DiffData

//}